So, rephrase it thus:

"Russia, Ukraine, and multiple international news agencies reported that Ukrainian drones targeted Moscow on or around May 18, 2026."

There are rarely pure first-order "facts" in the mathematical sense. There are evidence-backed claims with confidence levels. That does not make it "just a litmus test". It makes it a probabilistic factual claim with varying confidence levels - and this one happens to be verified and unambiguous.

Indeed. Real-world claims are somewhat messy. Some of the standard benchmarks, e.g. the questions in AVeriTeC, share similar characteristics.